Polybutylene plumbing pipe is becoming increasingly popular in new and existing building water pipe installations, replacing copper piping. In such plumbing systems, the fittings and the connecting pipes are constructed of polybutylene. Typically, the hollow fitting, such as an elbow, or a T-shaped fitting, is molded according to a certain size. The polybutylene pipe is then fitted over the appropriate projecting end on the fitting, and is secured firmly in place over the end of the fitting by crimping a metal ring onto the pipe where it overlaps onto the end of the fitting.
In crimping the ring onto the pipe, it is customary to use a crimping tool which resembles a common bolt cutter in that the crimping action is created by intersecting arms on a pivot with compound gears to provide leverage onto the crimping mechanism. A problem with the existing crimping tool is that the pivot fulcrum is located between the crimping end of the tool and the handles, thereby reducing leverage. Furthermore, the gears must be constantly adjusted in order to ensure that the crimping tool properly crimps the ring.
Another problem with the existing crimping tool is that since the fulcrum is between the crimping end and the user and it is therefore difficult in certain situations, such as where the piping is in the ceiling of an installation, for the installer to see the ring properly in order to ensure that the crimping end of the tool fits properly over the ring and properly crimps it onto the polybutylene pipe. In other words, the crimping tool obscures the ring from the vision of the installer.
A further problem with conventional crimping pliers is that the gears wear down and need periodic adjustment. Also, since the arms are long, it is not possible in many confined situations to apply the crimper to the crimp ring. An alternative type of crimping device such as a clamp must be used.
Several patents disclose various designs of crimping tools.
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 156,125 Blair October 20, 1874 1,482,888 Converse February 5, 1924 1,490,847 Petersen April 15, 1924 2,562,055 Miller July 24, 1951 2,819,634 Hansen January 14, 1958 4,769,891 Corral September 13, 1988 ______________________________________
Hansen discloses a rope and binding and ferrule clamping tool. Hansen shows transverse semicircular concave portions 34, 34', 36 and 36', of two separate diameters. Hansen also shows two ferrule deforming members 42 and 44, of different sizes.
Blair shows a hog-ringing nipper which has the hinge "b", at one end of the tool and the handles "c" at the opposite end.
Miller discloses a hose ferrule clamping plier which has a hinge 12 at one end, and handles 9 and 10 extending from the hinge. The clamping action is unusual because the hose ferrule is crimped in wire ring 15.
Converse discloses a tool for tipping shoe laces. The crimping mechanism and the handles are on opposite sides of the pivot point.
Peterson shows a clamp fastener wherein the clamp end 8 is separated from the handles 2 and 3 by the hinge 10.
Corral illustrates a hand tool for tube fittings which shows a leverage action between the handles 14 and 16 and the head portion 28.